1. Field of the Invention
This invention relates to an odometer for an automobile, and more particularly, to an odometer having a drive mechanism for preventing the reversing of the numbered wheels, thereby to prevent lesser reading than that which was actually counted.
2. Description of the Prior Art
A conventional odometer having such a drive mechanism is described in U.S. Pat. No. 3,516,603, wherein a link member having a first and second tab therewith is disposed between a drive gear on which a spiral cam groove formed and a least significant digit wheel and wherein the first tab is urged to move along the spiral groove in response to the rotating direction of the drive gear so that the second tab engages with the internal gear teeth of the least significant digit wheel in the forward rotation and disengages in the backward rotation. In the construction described above, since the second tab engages with and disengages from the internal gear teeth on account of the eccentricity of the spiral groove a half turn of the wheel is needed for the second tab to engage with the internal gear teeth upon returning to the forward rotation from the backward rotation, which obstructs accurate counting.